A waste lye desulfurization tail gas treatment system
By designing a waste alkaline solution desulfurization tail gas treatment system that includes a desulfurization unit, a tail gas pretreatment unit, and a tail gas co-treatment unit, the problem of high ammonia and benzene content in the desulfurization tail gas was solved, achieving compliant emissions and energy conservation and emission reduction effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHAANXI YANCHANG CHINACOAL YULIN ENERGY CHEM
- Filing Date
- 2025-08-27
- Publication Date
- 2026-08-04
AI Technical Summary
In existing technologies, the desulfurization tail gas contains high levels of ammonia and benzene compounds, resulting in substandard emissions. Conventional biological treatment processes cannot effectively remove these compounds.
Design a waste alkali solution desulfurization tail gas treatment system, including a desulfurization unit, a tail gas pretreatment unit, and a tail gas co-treatment unit. The desulfurization unit removes sulfides from the waste alkali solution, the tail gas pretreatment unit pre-treats pollutants, the tail gas co-treatment unit further treats them, and finally the system achieves compliant emissions through co-treatment by a cogeneration boiler.
It effectively reduces energy consumption, eliminates the construction and operation costs of tail gas incinerators, and achieves tail gas emissions that meet standards, complying with energy conservation and emission reduction requirements.
Smart Images
Figure CN224585662U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of alkali treatment technology, and in particular to a waste alkali desulfurization tail gas treatment system. Background Technology
[0002] Large-scale integrated utilization projects of coal, oil, and gas resources generate a large amount of waste alkaline liquid during the alkaline washing of acidic gas. The main units that generate acidic gas are residue catalytic thermal cracking (DCC) units and methanol-to-olefins (MTO) units. Taking the residue catalytic thermal cracking unit as an example, the waste alkaline liquid it emits contains a large amount of sulfides, ammonia nitrogen, and benzene compounds. Most of the sulfides are catalytically oxidized to sodium thiosulfate and sodium sulfate in the desulfurization reactor through aeration. A small amount of sulfur ions are in the form of hydrogen sulfide, most of the ammonia nitrogen is in the form of ammonia gas, and the vast majority of benzene compounds are directly stripped and carried into the desulfurization tail gas.
[0003] Conventional biological treatment devices are effective at removing low concentrations of ammonia, hydrogen sulfide, and readily biodegradable organic matter from waste gas. However, due to the unique cyclic structure of benzene compounds, conventional biological treatment processes are almost ineffective at removing them. Therefore, using biological treatment alone to treat desulfurization tail gas often leads to excessive benzene levels at the total discharge outlet of the treatment facility. Furthermore, because the ammonia content in desulfurization tail gas is high, simple biological treatment processes cannot achieve compliance. Therefore, it is necessary to design a waste alkaline solution desulfurization tail gas treatment method to remove ammonia and benzene compounds from the desulfurization tail gas, thereby meeting increasingly stringent environmental protection requirements. Utility Model Content
[0004] This application provides a waste alkali desulfurization tail gas treatment system, which solves the technical problem in the prior art where the high content of ammonia and benzene series compounds in the desulfurization tail gas leads to substandard tail gas emissions.
[0005] This utility model provides a waste alkali desulfurization tail gas treatment system, including a desulfurization unit, a tail gas pretreatment unit, and a tail gas co-treatment unit. The input end of the desulfurization unit is connected to a waste alkali discharge device, the liquid output end of the desulfurization unit is connected to a waste alkali resource utilization device, the gas output end of the desulfurization unit is connected to the input end of the tail gas pretreatment unit, and the output end of the tail gas pretreatment unit is connected to the tail gas co-treatment unit. The desulfurization unit is configured to remove sulfides from the waste alkali, the tail gas pretreatment unit is configured to perform preliminary treatment on the tail gas pollutants, and the tail gas co-treatment unit is configured to further treat the tail gas pollutants.
[0006] In one possible implementation, the desulfurization unit includes a regulating tank, a catalyst injection facility, a desulfurization aeration blower, and a desulfurization reactor; the input end of the regulating tank is connected to the waste alkali liquid discharge device, and the output end of the regulating tank is connected to the input end of the catalyst injection facility; the output end of the catalyst injection facility is connected to the liquid input end of the desulfurization reactor, and the desulfurization aeration blower is connected to the gas input end of the desulfurization reactor; the gas output end of the desulfurization reactor is connected to the input end of the tail gas pretreatment unit, and the liquid output end of the desulfurization reactor is connected to the waste alkali liquid resource utilization device.
[0007] In one possible implementation, the tail gas pretreatment unit includes an acid washing tower, a sulfuric acid dosing facility, a biological treatment stage, a tail gas conveying fan, and a condensate collection and transportation device; the first input end of the acid washing tower is connected to the gas output end of the desulfurization reactor, and the output end of the acid washing tower is connected to the input end of the biological treatment stage; the output end of the biological treatment stage is connected to the input end of the tail gas conveying fan, the first output end of the tail gas conveying fan is connected to the input end of the condensate collection and transportation device, the second output end of the tail gas conveying fan is connected to the tail gas co-treatment unit, and the output end of the condensate collection and transportation device is connected to the input end of the regulating tank; the sulfuric acid dosing facility is connected to the second input end of the acid washing tower.
[0008] In one possible implementation, the exhaust gas co-treatment unit includes a heat exchanger, a flame arrester, a cogeneration boiler, and a flue gas treatment device; the cold-side input end of the heat exchanger is connected to the second output end of the exhaust gas conveying fan, the hot-side input end of the heat exchanger is connected to the first output end of the cogeneration boiler, the cold-side output end of the heat exchanger is connected to the input end of the flame arrester, and the hot-side output end of the heat exchanger is connected to the flue gas treatment device; the output end of the flame arrester is connected to the input end of the cogeneration boiler; and the second output end of the cogeneration boiler is connected to the flue gas treatment device.
[0009] In one possible implementation, the desulfurization unit further includes a booster pump; the input of the booster pump is connected between the regulating tank and the catalyst injection facility.
[0010] In one possible implementation, the exhaust gas pretreatment unit further includes a circulation pump; one end of the circulation pump is connected to the third input end of the acid washing tower, and the other end of the circulation pump is connected to the fourth input end of the acid washing tower.
[0011] In one possible implementation, the exhaust gas pretreatment unit further includes a second biological treatment stage; the second biological treatment stage is connected between the first biological treatment stage and the exhaust gas conveying fan.
[0012] In one possible implementation, the exhaust gas co-treatment unit includes a flue gas booster fan; the flue gas booster fan is connected between the first output end of the cogeneration boiler and the hot-side input end of the heat exchanger.
[0013] One or more technical solutions provided in this application have at least the following technical effects:
[0014] This utility model embodiment employs a waste alkali solution desulfurization tail gas treatment system, including a desulfurization unit, a tail gas pretreatment unit, and a tail gas co-treatment unit. The input end of the desulfurization unit is connected to a waste alkali solution discharge device, the liquid output end of the desulfurization unit is connected to a waste alkali solution resource utilization device, the gas output end of the desulfurization unit is connected to the input end of the tail gas pretreatment unit, and the output end of the tail gas pretreatment unit is connected to the tail gas co-treatment unit. The desulfurization unit is configured to remove sulfides from the waste alkali solution, the tail gas pretreatment unit is configured to perform preliminary treatment on the tail gas pollutants, and the tail gas co-treatment unit is configured to further treat the tail gas pollutants. This application solves the technical problem in the prior art where the high content of ammonia and benzene series compounds in desulfurization tail gas leads to substandard tail gas emissions. After simple pretreatment, the desulfurization tail gas is co-treated by a cogeneration boiler, ultimately achieving compliant emissions, effectively reducing treatment energy consumption, and eliminating the construction and operation and maintenance costs of tail gas incinerators, thus meeting the requirements of energy conservation and emission reduction. Attached Figure Description
[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 This is a system diagram of a waste alkali desulfurization tail gas treatment system provided in an embodiment of this application.
[0017] Icons: 1-Desulfurization unit; 11-Regulating tank; 12-Catalyst dosing facility; 13-Desulfurization aeration fan; 14-Desulfurization reactor; 15-Boost pump; 2-Tail gas pretreatment unit; 21-Acid washing tower; 22-Sulfuric acid dosing facility; 23-Biological treatment stage 1; 24-Tail gas conveying fan; 25-Condensate collection and conveying device; 26-Circulating pump; 27-Biological treatment stage 2; 3-Tail gas co-treatment unit; 31-Heat exchanger; 32-Flame arrestor; 33-Cogeneration boiler; 34-Flue gas treatment device; 35-Flue gas booster fan. Detailed Implementation
[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.
[0019] In the description of the embodiments of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the embodiments of this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this utility model can be understood according to the specific circumstances.
[0020] This utility model provides a waste alkali solution desulfurization tail gas treatment system, such as Figure 1 As shown, the system includes a desulfurization unit 1, a tail gas pretreatment unit 2, and a tail gas co-treatment unit 3. The input end of the desulfurization unit 1 is connected to the waste alkali liquid discharge device, the liquid output end of the desulfurization unit 1 is connected to the waste alkali liquid resource utilization device, the gas output end of the desulfurization unit 1 is connected to the input end of the tail gas pretreatment unit 2, and the output end of the tail gas pretreatment unit 2 is connected to the tail gas co-treatment unit 3. The desulfurization unit 1 is configured to remove sulfides from the waste alkali liquid, the tail gas pretreatment unit 2 is configured to perform preliminary treatment on the tail gas pollutants, and the tail gas co-treatment unit 3 is configured to further treat the tail gas pollutants.
[0021] For example, desulfurization unit 1 removes sulfides from waste alkaline solution and transports the desulfurized waste alkaline solution to downstream treatment devices. The desulfurized tail gas enters tail gas pretreatment unit 2, where some easily degradable organic matter, such as ammonia and hydrogen sulfide, is removed. The pretreated tail gas then exchanges heat with flue gas discharged from cogeneration boiler 33 before being co-fired in the boiler furnace. This application solves the problem of excessively long treatment processes and high treatment costs caused by the complex composition of desulfurized tail gas. After simple pretreatment, the desulfurized tail gas is co-processed by cogeneration boiler 33, ultimately achieving emission standards, effectively reducing energy consumption, and eliminating the construction and maintenance costs of tail gas incinerators, thus meeting energy conservation and emission reduction requirements.
[0022] In the embodiments of this application, such as Figure 1 As shown, the desulfurization unit 1 includes a regulating tank 11, a catalyst injection facility 12, a desulfurization aeration blower 13, and a desulfurization reactor 14. The input end of the regulating tank 11 is connected to the waste alkali liquid discharge device, and the output end of the regulating tank 11 is connected to the input end of the catalyst injection facility 12. The output end of the catalyst injection facility 12 is connected to the liquid input end of the desulfurization reactor 14, and the desulfurization aeration blower 13 is connected to the gas input end of the desulfurization reactor 14. The gas output end of the desulfurization reactor 14 is connected to the input end of the tail gas pretreatment unit 2, and the liquid output end of the desulfurization reactor 14 is connected to the waste alkali liquid resource utilization device.
[0023] For example, the waste alkaline liquid from the catalytic pyrolysis of residual oil is homogenized in the regulating tank 11 and then transported to the desulfurization reactor 14 by the booster pump 15. The liquid catalyst, which is uniformly and continuously output by the catalyst dosing facility 12, is fully mixed with the waste alkaline liquid on the inlet pipeline of the booster pump 15 and then enters the desulfurization reactor 14. The desulfurization aeration blower 13 continuously aerates the desulfurization reactor 14 during the reaction. The outlet of the desulfurization aeration blower 13 is equipped with a vent valve, which can adjust the aeration rate according to the air volume required by the desulfurization reactor 14. The gas output end of the desulfurization reactor 14 is connected to the acid washing tower 21.
[0024] For example, the desulfurization reactor 14 is a plug flow reactor, in which the booster pump 15, catalyst injection facility 12, and desulfurization aeration blower 13 all operate continuously. To increase the reaction residence time, the desulfurization reactor 14 can be configured with multiple reactors connected in series. The gas output end of the desulfurization reactor 14 is equipped with an online oxygen content detector, which can adjust the aeration rate in real time according to the oxygen utilization rate.
[0025] In the embodiments of this application, such as Figure 1As shown, the exhaust gas pretreatment unit 2 includes an acid washing tower 21, a sulfuric acid dosing facility 22, a biological treatment stage 23, an exhaust gas conveying fan 24, and a condensate collection and conveying device 25. The first input end of the acid washing tower 21 is connected to the gas output end of the desulfurization reactor 14, and the output end of the acid washing tower 21 is connected to the input end of the biological treatment stage 23. The output end of the biological treatment stage 23 is connected to the input end of the exhaust gas conveying fan 24, the first output end of the exhaust gas conveying fan 24 is connected to the input end of the condensate collection and conveying device 25, the second output end of the exhaust gas conveying fan 24 is connected to the exhaust gas co-treatment unit 3, and the output end of the condensate collection and conveying device 25 is connected to the input end of the regulating tank 11. The sulfuric acid dosing facility 22 is connected to the second input end of the acid washing tower 21.
[0026] For example, the acid washing tower 21 removes high-concentration ammonia from the tail gas through a matching circulating pump 26 and sulfuric acid dosing facility 22. An online pH meter is installed on the outlet pipeline of the circulating pump 26. After the acidic substances in the circulating pump 26 react with the ammonia, the pH of the circulating liquid will rise, requiring periodic replenishment of the system with strong inorganic acid. Simultaneously, the nearly saturated ammonium sulfate solution needs to be periodically discharged from the acid washing tower 21 to ensure the ammonia removal rate. Residual ammonia, hydrogen sulfide, and easily degradable organic matter in the tail gas exiting the acid washing tower 21 can be effectively removed in the first stage of biological treatment 23 and the second stage of biological treatment 27. The tail gas conveying fan 24 continuously provides power for tail gas conveying. During the tail gas conveying process, the saturated water vapor in the tail gas condenses and is returned to the regulating tank 11 of the desulfurization unit 1 through the condensate collection and conveying device 25.
[0027] For example, the ammonia content in the desulfurization tail gas at the inlet of acid washing tower 21 is approximately 500 mg / m³. 3 The ammonia content in the desulfurization tail gas at the outlet of pickling tower 21 is approximately 50 mg / m³. 3 .
[0028] In the embodiments of this application, such as Figure 1 As shown, the exhaust gas co-treatment unit 3 includes a heat exchanger 31, a flame arrester 32, a cogeneration boiler 33, and a flue gas treatment device 34; the cold-side input end of the heat exchanger 31 is connected to the second output end of the exhaust gas conveying fan 24, the hot-side input end of the heat exchanger 31 is connected to the first output end of the cogeneration boiler 33, the cold-side output end of the heat exchanger 31 is connected to the input end of the flame arrester 32, and the hot-side output end of the heat exchanger 31 is connected to the flue gas treatment device 34; the output end of the flame arrester 32 is connected to the input end of the cogeneration boiler 33; and the second output end of the cogeneration boiler 33 is connected to the flue gas treatment device 34.
[0029] For example, the flue gas booster fan 35 is a variable frequency fan, which can adjust the flue gas flow rate at the hot side input of the heat exchanger 31 according to the temperature requirements of the cold side output of the heat exchanger 31. The combined heat and power boiler 33 is a highly efficient energy utilization technology that simultaneously produces electricity and chemical steam through a single energy input. Its core advantage lies in the cascade utilization of energy, with a comprehensive efficiency of 70%-90%, far exceeding that of traditional stand-alone power generation (approximately 35%-50%). It combines energy saving, environmental protection, and economy. In the event of a single boiler interlock trip, it can urgently stop the power-side heat load, cleverly achieving boiler hot standby. While improving the reliability of chemical steam use, it ensures that the boiler operates at high load for the vast majority of the time, further saving energy.
[0030] For example, a flame arrester 32 is installed after the heat exchanger 31 to prevent backfire when the boiler furnace air pressure and the tail gas delivery pipeline pressure are abnormal.
[0031] In the embodiments of this application, such as Figure 1 As shown, the desulfurization unit 1 also includes a booster pump 15; the input end of the booster pump 15 is connected between the regulating tank 11 and the catalyst injection facility 12.
[0032] In the embodiments of this application, such as Figure 1 As shown, the exhaust gas pretreatment unit 2 also includes a circulation pump 26; one end of the circulation pump 26 is connected to the third input end of the acid washing tower 21, and the other end of the circulation pump 26 is connected to the fourth input end of the acid washing tower 21.
[0033] In the embodiments of this application, such as Figure 1 As shown, the exhaust gas pretreatment unit 2 also includes a biological treatment stage 27; the biological treatment stage 27 is connected between the biological treatment stage 23 and the exhaust gas conveying fan 24.
[0034] In the embodiments of this application, such as Figure 1 As shown, the exhaust gas co-processing unit 3 includes a flue gas booster fan 35; the flue gas booster fan 35 is connected between the first output end of the cogeneration boiler 33 and the hot side input end of the heat exchanger 31.
[0035] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.
[0036] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.
Claims
1. A waste alkali solution desulfurization tail gas treatment system, characterized in that, It includes a desulfurization unit (1), a tail gas pretreatment unit (2), and a tail gas co-treatment unit (3); The input end of the desulfurization unit (1) is connected to the waste alkali liquid discharge device, the liquid output end of the desulfurization unit (1) is connected to the waste alkali liquid resource utilization device, the gas output end of the desulfurization unit (1) is connected to the input end of the tail gas pretreatment unit (2), and the output end of the tail gas pretreatment unit (2) is connected to the tail gas co-treatment unit (3). The desulfurization unit (1) is configured to remove sulfides from the waste alkaline solution, the tail gas pretreatment unit (2) is configured to perform preliminary treatment on the tail gas pollutants, and the tail gas co-treatment unit (3) is configured to perform further treatment on the tail gas pollutants.
2. The spent caustic desulphurization off-gas treatment system as claimed in claim 1, wherein, The desulfurization unit (1) includes a regulating tank (11), a catalyst injection facility (12), a desulfurization aeration blower (13), and a desulfurization reactor (14); The input end of the regulating tank (11) is connected to the waste alkali discharge device, and the output end of the regulating tank (11) is connected to the input end of the catalyst injection facility (12). The output end of the catalyst injection facility (12) is connected to the liquid input end of the desulfurization reactor (14), and the desulfurization aeration blower (13) is connected to the gas input end of the desulfurization reactor (14). The gas output end of the desulfurization reactor (14) is connected to the input end of the tail gas pretreatment unit (2), and the liquid output end of the desulfurization reactor (14) is connected to the waste alkali liquid resource utilization device.
3. The waste alkali liquid desulfurization tail gas treatment system according to claim 2, characterized in that, The exhaust gas pretreatment unit (2) includes an acid washing tower (21), a sulfuric acid dosing facility (22), a biological treatment stage (23), an exhaust gas conveying fan (24), and a condensate collection and conveying device (25); The first input end of the acid washing tower (21) is connected to the gas output end of the desulfurization reactor (14), and the output end of the acid washing tower (21) is connected to the input end of the biological treatment section (23). The output end of the biological treatment section (23) is connected to the input end of the exhaust gas conveying fan (24), the first output end of the exhaust gas conveying fan (24) is connected to the input end of the condensate collection and conveying device (25), the second output end of the exhaust gas conveying fan (24) is connected to the exhaust gas co-processing unit (3), and the output end of the condensate collection and conveying device (25) is connected to the input end of the regulating tank (11). The sulfuric acid dosing facility (22) is connected to the second input end of the acid washing tower (21).
4. The spent caustic desulphurization off-gas treatment system as claimed in claim 3, wherein, The exhaust gas co-processing unit (3) includes a heat exchanger (31), a flame arrester (32), a cogeneration boiler (33), and a flue gas treatment device (34); The cold-side input end of the heat exchanger (31) is connected to the second output end of the exhaust gas conveying fan (24), the hot-side input end of the heat exchanger (31) is connected to the first output end of the cogeneration boiler (33), the cold-side output end of the heat exchanger (31) is connected to the input end of the flame arrester (32), and the hot-side output end of the heat exchanger (31) is connected to the flue gas treatment device (34). The output end of the flame arrester (32) is connected to the input end of the cogeneration boiler (33); The second output end of the cogeneration boiler (33) is connected to the flue gas treatment device (34).
5. The spent caustic desulphurization off-gas treatment system as claimed in claim 2, wherein, The desulfurization unit (1) also includes a booster pump (15); The input end of the booster pump (15) is connected between the regulating tank (11) and the catalyst injection facility (12).
6. The spent caustic desulphurization off-gas treatment system as claimed in claim 3, wherein, The exhaust gas pretreatment unit (2) also includes a circulation pump (26); One end of the circulating pump (26) is connected to the third input end of the pickling tower (21), and the other end of the circulating pump (26) is connected to the fourth input end of the pickling tower (21).
7. The spent caustic desulphurization off-gas treatment system as claimed in claim 3, wherein, The exhaust gas pretreatment unit (2) also includes a biological treatment stage (27); The second biological treatment stage (27) is connected between the first biological treatment stage (23) and the exhaust gas conveying fan (24).
8. The spent caustic desulphurization off-gas treatment system as claimed in claim 4 wherein, The exhaust gas co-treatment unit (3) includes a flue gas booster fan (35); The flue gas booster fan (35) is connected between the first output end of the cogeneration boiler (33) and the hot side input end of the heat exchanger (31).